Insulating material and method of producing the same.



UNITED STATES PATENT OFFICE.

CHARLES NORTON, OF MANCHESTER, MASSACHUSETTS, ASSIGNOR TO ASBESTOSCOMPANY, A CORPORATION OF MAINE.

WOOD

INSULATING MATERIAL AND METHOD OF PRODUCING THE- SAME.

To all whom it may concern:

Be it known that I, CHARLES L. NORTON, acitizen of the United States,and a resident of Manchester, in the county of Essex and State ofMassachusetts, have invented new and useful Improvements in InsulatingMaterial and Methods of Producing the Same, of which the following is aspecification. Y

My invention consists iu a new material or composition suitable for useas an insulator in electrical apparatus, and in the method of producingsuch insulating material. Incidentally the practice of my new processresults in the production of a material of superiormechanical strengthand resistance to the action of water and may, therefore, commend itselfto uses not necessarily connected with the construction or operation ofelectrical apparatus, although I believe that the chief value of myprocess and the product produced thereby lies in its adaptability toinsulating purposes in the construction and operation of electrical.apparatus.

In my application for Letters Patent of the United States filed June 7,1906, Serial No. 320,670 for refractory materials and process forproducing them there is set forth a process for making a refractorymaterial of asbestos or asbestiform fiber, bonded with magnesiumhydrate. This refractory material is, I believe, the best available forthe practice of my process presently to be described and the obtainmentof the new product. Asbestiform fiber bonded with magnesium hydrate is aporous body which contains within its structure a proportion ofmagnesium hydroxid as a free oxidizing agent, and for this reason, as Ibelieve, the

refractory material of my application aforesaid is parprocess.

ticularly welladapted to the practice of my present I take a porousmaterial preferably composed in large part of refractory substances andwhich contains within its body a free oxidizing agent, such asasbestiform fiber bonded with magnesium hydrate described in myapplication aforesaid, and impregnate it with a liquefiable, oxidizablehydrocarbon; and allow the hydrocarbon thus introduced into the pores ofthe body to set and, harden in association with the materials with whichthe body is in whole or in part composed. More specifically, I take therefractory material described in my application aforesaid in itscompleted dry state and then further dryit by the application of heat ascompletely as possible without expelling the chemically combined water.Next, either by heating or by exhaustion with an air pump or both,Iwithdraw most of the air from the pores of the material and while thematerial is in a heated, dry and air-exhausted condition, I immetse'itin a liquid hydrocarbon or hydrocarbon compound and when the liquid haspenetrated the pores of the material, I- remove it from theSpecification of Letters Patent. Application filed February 23, 1907Serial No. 858,894:

Patented Sept. 10, 1907- while: its diminished porosity renders itpractically non-'hydroscopic.

The liquid or liquid compound which I employ for impregnating therefractory material referred to, is a liquefiable and oxidizablehydrocarbon, preferably one which is either very soft or a liquid atordinary temperatures or undermoderate heat. This may be a mixture ofseveral hydrocarbons and I have found it to be immaterial whether or notthe composition be a liquid at ordinary temperatures of the air, for thereason that after the refractory material is impregnated with thehydrocarbon, the mutual action of the refractory material and thehydrocarbon is such as to harden the hydro-. carbon in the pores of therefractory material. For the impregnating liquid I may use pitches orasphalts, notably those which contain ceresin wax, among them themineral ozocerite, or infact, any other insulating hydrocarbon which,when heated and absorbed into the pores of they refractory material,becomes set or hardened through the action of the substances comprisingsubstance called minwax which is a mineral wax or pitch of about theconsistency of molasses at an ordinary temperature and, as abovedescribed, impregnate the refractory material with it; the resultingproduct will be hard, capable of receivinga high polish and having asharp clean fracture which shows thatthe alteration of the hydrocarbonoccurs not only on the surface but throughout the body of the materialwherever the hydrocarbon has penetrated. It appears that the mag-.nesium hydroxid-or oxid, "or a slight amount of uncalcined magnesia inthe refractory material described in my application aforesaid, combineswith the hydrocarbon in such a way as' to make it much harder than itordinarily is. The operation appears to be equivalent in some measure tothe well known process of distillation of the lighter and more volatileportions of the hydrocarbon, although in my process I accomplish thewhole operation at a temperature much lower than that usually requiredto accomplish the distillation of the volatile products. It may be,onthe other hand, that the magnesia compounds which are contained in therefractory material have a capacity for-combination with the harderingredients of the hydrocarbon pitches to the exclusion of the lighterand more volatile, ones;

suchabsorption and combination would be the equivalent, in its netresult, for a distillation process although conducted at a lowertemperature than that usually required for distillation.

I have found that if a soft asphalt or pitch or similar 5" hydrocarbonbe absorbed into a porous material other than that described in myapplication aforesaid, it can be hardened therein by actual distillationof the lighter and more volatile ingredients, but the loss in volume dueto distillation leaves the pores of the material incompletely filled.

Whether or not the foregoing be the true explanation of the action whichtakes place, it is certain that when a liquefiable and oxidizablehydrocarbon of the class whereof ozocerite is a type, is absorbed in aliquid condition into the pores of the refractory material, such asdescribed in my application aforesaid, and there allowed to harden inassociation with the free oxidizing agents which reside in the body ofthe material, it results in a product which is harder, stronger, capableof a higher polish, practically impervious to water, possessing greatinsulating powers and dielectric strength and capable of being workedwith tools, and which has also this great advantage over other fiber andpitch insulators in that it has a refractory skeleton which, should thesoftening temperature of the hardened hydr'ocarbon be exceeded, willstill serve to make the material keep its shape and retain aconsiderable proportion of its strength.

hydrocarbon to harden in the body by association with magnesiumhydroxid.

body containing magnesium hydroxid with a liqueiiableoxodizablehydrocarbon.

7. The process which consists in impregnating a body composed ofasbestiform fiber bonded with magnesium hydrate, with a liquefinbleoxidizable hydrocarbon.

S. The process which consists in heating a porous body containingmagnesium hydroxid, impregnating it while heated with a liquefiablehydrocarbon, and allowing the hydrocarbon to harden in the body.

9. The process which consists in heating a body composed of asbestiformfiber bonded with magnesium hydrate, impregnating it while heated with aliquefiable hydrocariron, and allowing the hydrocarbon to harden in thebody.

10. The process which consists in heating a porous body containingmagnesium hydroxid and impregnating it while heated with a liquefiableoxidizable hydrocarbon.

11. The process which consists in heating a body composed of asbestiformfiber bonded with magnesium hydrate, and impregnating it while heatedwith a liquefiable oxidizable hydrocarbon.

12. The product consisting of a porous body containing magnesiumhydroxid, impregnated with an oxidized hydrocarbon. I

13. The product consisting of asbestiform fiber bonded with magnesiumhydrate, impregnated with an oxidized hydrocarbon.

14. The product consisting of a porous body containing magnesiumhydroxid, impregnated with an oxidized hydrocarbon of the class whereofozocerite is a type.

15. The product consisting of asbestiform fiber bonded with magnesiumhydrate, impregnated with an oxidized hydrocarbon of the class whereofozocerite is a type.

Signed by me at Boston, Massachusetts, this 15th day of February, 1907.

CHARLES L. NORTON.

Witnesses JOSEPH T. BRENNAN, CHARLES D. Woonnnrmr.

